Table 1. MUSICO parameters for the simulations of twitch contractions in intact rat trabeculae at fixed length and at temperature 27.2°C in Fig. 5 (Caremani et al., 2016) and at 27.5°C in Fig. 6 (Janssen et al., 2002).

Description	Parameter	Isometric trabeculae	Notes
Cross-bridge cycle
Myosin–actin binding rate	$k_{+A}^o$	226 s−1
Myosin–actin detachment ratea	$k_{-A}^o$	46 s−1
Myosin stroke cap rate	$k_{\mathit{+}Pi}^{cap}$	1,000 s−1	Mijailovich et al., 2016, 2019
Myosin reverse stroke cap rate	$k_{\mathit{-}Pi}^{cap}$	100 s−1	Mijailovich et al., 2016, 2019
Power stroke Gibbs energy change	$\Delta G_{stroke}$	−13 $k_{B}T$	Mijailovich et al., 2016, 2019
Working stroke	$d$	10.5 nm	Duke, 1999; Mijailovich et al., 2016, 2019
Second working stroke	$\mathrm{\delta }$	1 nm	Mijailovich et al., 2016, 2019
ADP release ratea	$k_{\mathit{+}\mathit{D}}^{\mathit{o}}$	60 s−1
ATP binding and myosin detachmenta	$k_{\mathit{+}\mathit{T}}$	106 s−1
Hydrolysis forward ratea	$k_{+H}$	100 s−1
Hydrolysis backward ratea	$k_{-H}$	10 s−1
Cross-bridge stiffness	$\kappa$	1.3 pN/nm	Duke, 1999; Mijailovich et al., 2016, 2019
$k_{B}T$ at 27.5°C	$k_{\mathit{B}}T$	4.147 pN·nm
Calcium kinetics
Calcium binding to TnC equilibrium rate	${\tilde{\mathit{K}}}_{\mathit{C}\mathit{a}}$	1 µM−1	Smith and Geeves, 2003; Geeves et al., 2011
Calcium binding rate to TnC	${\tilde{k}}_{Ca}$	75.4 µM−1·s−1	Smith and Geeves, 2003; Geeves et al., 2011
Calcium dissociation rate from TnC	$k_{-Ca}$	75.4 s−1	Kreutziger et al., 2011; Wang et al., 2012, 2013
TnI–actin equilibrium rate constant At high Ca2+	$\mathrm{\lambda }$	10
TnI–actin backward rate constant	${\mathrm{\lambda }}_{-}$	375 s−1
Allosteric TnC–TnI–actin–Ca2+ parameter	${\mathrm{\epsilon }}_o$	0.01	Smith and Geeves, 2003; Geeves et al., 2011
CFC
Tpm pinning angle	${\varphi }_{-}$	−25°	Poole et al., 2006
Myosin Tm angular displacements	${\varphi }_{+}$	10°	Poole et al., 2006
Angular SD of free CFC	${\sigma }_0$	29.7°	Pirani et al., 2005; Mijailovich et al., 2012
Persistence length of Tm–Tn confined chain	$1\mathrm{/\xi }$	50 nm	Mijailovich et al., 2012
PS
Transition rate to PS	$k_{-PS}$	200 s−1	Assumed
Baseline rate	$k_{PS}^0$	5 s−1	Assumed
Amplitude	$k_{PS}^{max}$	400 s−1	Assumed
Calcium Hill function slope	$b$	5	Assumed
Half-activation point of the Hill function	${[C{a}^{2+}]}_{50}$	1 µM	Assumed
Sarcomere
Length of sarcomere	$SL$	2.2 µm
Length of actin filament	$L_a$	1.1 µm	Robinson and Winegrad, 1977, 1979
Interfilament spacing	$d_{10}$	33.83 nm	Irving and Maughan, 2000
Thin-filament elastic modulus	$A{E}_a$	65 nN	Huxley et al., 1994; Kojima et al., 1994
Thick-filament elastic modulus	$A{E}_m$	132 nN	Huxley et al. 1994

^aBased on mouse and human α myosin values in (Deacon et al., 2012a, 2012b) with corrections for temperature; ionic strength is as documented in (Mijailovich et al., 2017).